'\" et
.TH PTHREAD_ATTR_GETSCHEDPARAM "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
pthread_attr_getschedparam,
pthread_attr_setschedparam
\(em get and set the schedparam attribute
.SH SYNOPSIS
.LP
.nf
#include <pthread.h>
.P
int pthread_attr_getschedparam(const pthread_attr_t *restrict \fIattr\fP,
    struct sched_param *restrict \fIparam\fP);
int pthread_attr_setschedparam(pthread_attr_t *restrict \fIattr\fP,
    const struct sched_param *restrict \fIparam\fP);
.fi
.SH DESCRIPTION
The
\fIpthread_attr_getschedparam\fR()
and
\fIpthread_attr_setschedparam\fR()
functions, respectively, shall get and set the scheduling parameter
attributes in the
.IR attr
argument. The contents of the
.IR param
structure are defined in the
.IR <sched.h> 
header. For the SCHED_FIFO and SCHED_RR policies,
the only required member of
.IR param
is
.IR sched_priority .
.P
For the SCHED_SPORADIC policy, the required members of the
.IR param
structure are
.IR sched_priority ,
.IR sched_ss_low_priority ,
.IR sched_ss_repl_period ,
.IR sched_ss_init_budget ,
and
.IR sched_ss_max_repl .
The specified
.IR sched_ss_repl_period
must be greater than or equal to the specified
.IR sched_ss_init_budget
for the function to succeed; if it is not, then the function shall
fail. The value of
.IR sched_ss_max_repl
shall be within the inclusive range [1,\c
{SS_REPL_MAX}]
for the function to succeed; if not, the function shall fail.
It is unspecified whether the
.IR sched_ss_repl_period
and
.IR sched_ss_init_budget
values are stored as provided by this function or are rounded to
align with the resolution of the clock being used.
.P
The behavior is undefined if the value specified by the
.IR attr
argument to
\fIpthread_attr_getschedparam\fR()
or
\fIpthread_attr_setschedparam\fR()
does not refer to an initialized thread attributes object.
.SH "RETURN VALUE"
If successful, the
\fIpthread_attr_getschedparam\fR()
and
\fIpthread_attr_setschedparam\fR()
functions shall return zero; otherwise, an error number shall be
returned to indicate the error.
.SH ERRORS
The
\fIpthread_attr_setschedparam\fR()
function shall fail if:
.TP
.BR ENOTSUP
An attempt was made to set the attribute to an unsupported value.
.P
The
\fIpthread_attr_setschedparam\fR()
function may fail if:
.TP
.BR EINVAL
The value of
.IR param
is not valid.
.P
These functions shall not return an error code of
.BR [EINTR] .
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
After these attributes have been set, a thread can be created with the
specified attributes using
\fIpthread_create\fR().
Using these routines does not affect the current running thread.
.SH RATIONALE
If an implementation detects that the value specified by the
.IR attr
argument to
\fIpthread_attr_getschedparam\fR()
or
\fIpthread_attr_setschedparam\fR()
does not refer to an initialized thread attributes object, it is
recommended that the function should fail and report an
.BR [EINVAL] 
error.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.ad l
.IR "\fIpthread_attr_destroy\fR\^(\|)",
.IR "\fIpthread_attr_getscope\fR\^(\|)",
.IR "\fIpthread_attr_getinheritsched\fR\^(\|)",
.IR "\fIpthread_attr_getschedpolicy\fR\^(\|)",
.IR "\fIpthread_create\fR\^(\|)"
.ad b
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<pthread.h>\fP",
.IR "\fB<sched.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
